Method of closing an opening in a wall of the heart

ABSTRACT

Disclosed is a closure catheter, for closing a tissue opening such as an atrial septal defect, patent foreman ovale, or the left atrial appendage of the heart. The closure catheter carries a plurality of tissue anchors, which may be deployed into tissue surrounding the opening, and used to draw the opening closed. Methods are also disclosed.

This application is a continuation of application Ser. No. 14/101,122,filed Dec. 9, 2013, which is a continuation of application Ser. No.13/477,404, filed May 22, 2012, now U.S. Pat. No. 8,603,108, which is acontinuation of application Ser. No. 11/880,265, filed on Jul. 20, 2007,which is a continuation of application Ser. No. 10/810,990, filed Mar.26, 2004, now U.S. Pat. No. 7,780,683, which is a continuation ofapplication Ser. No. 09/904,790, filed on Jul. 13, 2001, now U.S. Pat.No. 6,712,804, which is a divisional of application Ser. No. 09/444,904,filed on Nov. 22, 1999, now U.S. Pat. No. 6,290,674, which is acontinuation-in-part of application Ser. No. 09/399,521, filed Sep. 20,1999, now U.S. Pat. No. 6,231,561.

The present invention relates to methods and devices for closing a bodylumen, tissue opening, or cavity and, in particular, for closing anatrial septal defect.

BACKGROUND OF THE INVENTION

Embolic stroke is the nation's third leading killer for adults, and is amajor cause of disability. There are over 700,000 strokes per year inthe United States alone. Of these, roughly 100,000 are hemoragic, and600,000 are ischemic (either due to vessel narrowing or to embolism).The most common cause of embolic stroke emanating from the heart isthrombus formation due to atrial fibrillation. Approximately 80,000strokes per year are attributable to atrial fibrillation. Atrialfibrillation is an arrhythmia of the heart that results in a rapid andchaotic heartbeat that produces lower cardiac output and irregular andturbulent blood flow in the vascular system. There are over five millionpeople worldwide with atrial fibrillation, with about four hundredthousand new cases reported each year. Atrial fibrillation is associatedwith a 500 percent greater risk of stroke due to the condition. Apatient with atrial fibrillation typically has a significantly decreasedquality of life due, in part, to the fear of a stroke, and thepharmaceutical regimen necessary to reduce that risk.

For patients who develop atrial thrombus from atrial fibrillation, theclot normally occurs in the left atrial appendage (LAA) of the heart.The LAA is a cavity which looks like a small finger or windsock andwhich is connected to the lateral wall of the left atrium between themitral valve and the root of the left pulmonary vein. The LAA normallycontracts with the rest of the left atrium during a normal heart cycle,thus keeping blood from becoming stagnant therein, but often fails tocontract with any vigor in patients experiencing atrial fibrillation dueto the discoordinate electrical signals associated with AF. As a result,thrombus formation is predisposed to form in the stagnant blood withinthe LAA.

Blackshear and Odell have reported that of the 1288 patients withnon-rheumatic atrial fibrillation involved in their study, 221 (17%) hadthrombus detected in the left atrium of the heart. Blackshear J L, OdellJ A., Appendage Obliteration to Reduce Stroke in Cardiac SurgicalPatients With Atrial Fibrillation. Ann Thorac. Surg., 1996.61(2):755-9.Of the patients with atrial thrombus, 201 (91%) had the atrial thrombuslocated within the left atrial appendage. The foregoing suggests thatthe elimination or containment of thrombus formed within the LAA ofpatients with atrial fibrillation would significantly reduce theincidence of stroke in those patients.

Pharmacological therapies for stroke prevention such as oral or systemicadministration of warfarin or the like have been inadequate due toserious side effects of the medications and lack of patient compliancein taking the medication. Invasive surgical or thorascopic techniqueshave been used to obliterate the LAA, however, many patients are notsuitable candidates for such surgical procedures due to a compromisedcondition or having previously undergone cardiac surgery. In addition,the perceived risks of even a thorascopic surgical procedure oftenoutweigh the potential benefits. See Blackshear and Odell, above. Seealso Lindsay B D., Obliteration of the Left Atrial Appendage: A ConceptWorth Testing, Ann Thorac. Surg., 1996.61(2):515.

Despite the various efforts in the prior art, there remains a need for aminimally invasive method and associated devices for reducing the riskof thrombus formation in the left atrial appendage.

Other conditions which would benefit from a tissue aperture closurecatheter are tissue openings such as an atrial septal defect. Ingeneral, the heart is divided into four chambers, the two upper beingthe left and right atria and the two lower being the left and rightventricles. The atria are separated from each other by a muscular wall,the interatrial septum, and the ventricles by the interventricularseptum.

Either congenitally or by acquisition, abnormal openings, holes orshunts can occur between the chambers of the heart or the great vessels(interatrial and interventricular septal defects or patent ductusarteriosus and aorthico-pulmonary window respectively), causing shuntingof blood through the opening. The ductus arteriosus is the prenatalcanal between the pulmonary artery and the aortic arch which normallycloses soon after birth. The deformity is usually congenital, resultingfrom a failure of completion of the formation of the septum, or wall,between the two sides during fetal life when the heart forms from afolded tube into a four-chambered, two unit system.

These deformities can carry significant sequelae. For example, with anatrial septal defect, blood is shunted from the left atrium of the heartto the right, producing an over-load of the right heart. In addition toleft-to-right shunts such as occur in patent ductus arteriosus from theaorta to the pulmonary artery, the left side of the heart has to workharder because some of the blood which it pumps will recirculate throughthe lungs instead of going out to the rest of the body. The ill effectsof these lesions usually cause added strain on the heart with ultimatefailure if not corrected.

Previous extracardiac (outside the heart) or intracardiac septal defectshave required relatively extensive surgical techniques for correction.To date the most common method of closing intracardiac shunts, such asatrial-septal defects and ventricular-septal defects, entails therelatively drastic technique of open-heart surgery, requiring openingthe chest or sternum and diverting the blood from the heart with the useof a cardiopulmonary bypass. The heart is then opened, the defect issewn shut by direct suturing with or without a patch of syntheticmaterial (usually of Dacron, Teflon, silk, nylon or pericardium), andthen the heart is closed. The patient is then taken off thecardiopulmonary bypass machine, and then the chest is closed.

In place of direct suturing, closures of interauricular septal defectsby means of a mechanical prosthesis have been disclosed.

U.S. Pat. No. 3,874,388 to King, et al. relates to a shunt defectclosure system including a pair of opposed umbrella-like elements lockedtogether in a face to face relationship and delivered by means of acatheter, whereby a defect is closed. U.S. Pat. No. 5,350,399 toErlebacher, et al. relates to a percutaneous arterial puncture sealdevice also including a pair of opposed umbrella-like elements and aninsertion tool.

U.S. Pat. No. 4,710,192 to Liotta, et al. relates to a vaulted diaphragmfor occlusion in a descending thoracic aorta.

U.S. Pat. No. 5,108,420 to Marks relates to an aperture occlusion deviceconsisting of a wire having an elongated configuration for delivery tothe aperture, and a preprogrammed configuration including occlusionforming wire segments on each side of the aperture.

U.S. Pat. No. 4,007,743 to Blake relates to an opening mechanism forumbrella-like intravascular shunt defect closure device having foldableflat ring sections which extend between pivotable struts when the deviceis expanded and fold between the struts when the device is collapsed.

Notwithstanding the foregoing, there remains a need for a transluminalmethod and apparatus for correcting intracardiac septal defects, whichenables a patch to placed across a septal defect to inhibit or preventthe flow of blood therethrough.

SUMMARY OF THE INVENTION

The present invention provides a closure catheter and methods forclosing an opening in tissue, a body lumen, hollow organ or other bodycavity. The catheter and methods of its use are useful in a variety ofprocedures, such as treating (closing) wounds and naturally orsurgically created apertures or passageways. Applications include, butare not limited to, atrial septal defect closure, patent ductusarteriosis closure, aneurysm isolation and graft and/or bypassanostomosis procedures.

There is provided in accordance with one aspect of the present inventiona method of closing an opening in a wall of the heart. The methodcomprises the steps of advancing a catheter through the opening, anddeploying at least two suture ends from the catheter and into tissueadjacent the opening. The catheter is retracted from the opening, andthe suture ends are drawn toward each other to reduce the size of theopening. The opening is thereafter secured in the reduced size.

In one embodiment, the advancing step comprises advancing the catheterthrough an atrial septal defect. The deploying step comprises deployingat least four suture ends. Preferably, each suture end is provided witha tissue anchor, and the deploying step comprises advancing the tissueanchors into tissue adjacent the opening. The securing step comprisesknotting the sutures, clamping the sutures, adhesively bonding thesutures and/or the tissue to retain the opening in the reduced size.

In accordance with another aspect of the present invention, there isprovided an atrial septal closure catheter. The catheter comprises anelongate flexible body, having a proximal end and a distal end, and alongitudinal axis extending therebetween. At least two supports areprovided on the distal end, the supports moveable from a first positionin which there are substantially parallel with the axis, and a secondposition in which they are inclined with respect to the axis. A controlis provided on the proximal end for moving the supports from the firstposition to the second position. In one embodiment, the supports inclineradially outwardly in the proximal direction when the supports are inthe second position.

Preferably, the closure catheter comprises at least four supports, andeach support carries at least one anchor. Each anchor is preferablyprovided with an anchor suture.

In accordance with a further aspect of the present invention, there isprovided a method for closing an opening in a wall of the heart. Themethod comprises the steps of providing a catheter having at least threetissue anchors thereon, each tissue anchor having a suture securedthereto. The catheter is advanced to the opening in the wall of theheart, and the anchors are inclined outwardly from the axis of thecatheter to aim the anchors at tissue surrounding the opening. Theanchors are deployed into tissue surrounding the opening, and thesutures are manipulated to reduce the size of the openings.

In one embodiment, the deploying the anchors step comprises deployingthe anchors in a proximal direction. In another embodiment, thedeploying the anchors step comprises deploying the anchors in a distaldirection.

In accordance with a further aspect of the present invention, there isprovided a closure catheter for closing an atrial septal defect. Thecatheter comprises an elongate flexible tubular body, having a proximalend and a distal end, and a longitudinal axis extending therebetween. Atleast two anchor supports are provided on the distal end, the anchorsupports moveable between an axial position in which they aresubstantially parallel with the longitudinal axis, and an inclinedposition in which they are inclined laterally away from the axis. Acontrol is provided on the proximal end, for moving the anchor supportsbetween the axial and the inclined positions. Each anchor support has aproximal end and a distal end, and the distal end is pivotably securedto the catheter so that the proximal end moves away from the axis whenthe anchor support is moved into the inclined position.

In one embodiment, the closure catheter further comprises an anchor ineach of the anchor supports. Preferably, from about four to about 10anchor supports are each provided with an anchor. Each anchor ispreferably connected to a suture.

In one embodiment, a retention structure is removably carried by thedistal end of the catheter or slideably carried by the suture. Theretention structure is adapted to be distally advanced such that itconstricts around the sutures, thereby securing them in a desiredposition. In one embodiment, the retention structure comprises aslideable knot, such as a Prusik knot.

Further features and advantages of the present invention will becomeapparent to those of skill in the art in view of the detaileddescription of preferred embodiments which follows, when consideredtogether with the attached drawings and claims.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an anterior illustration of a heart, with the proximal partsof the great vessels.

FIG. 2 is a schematic cross section through the heart with a transeptalcatheter deployed through the septum and a closure catheter extendinginto the LAA.

FIG. 3A is an enlarged perspective view of the distal end of a closurecatheter in accordance with the present invention.

FIG. 3B is a cross section taken along the lines 3B-3B of FIG. 3A.

FIG. 4 is a partial cross-sectional view of a tissue anchor andintroducer, positioned within an anchor guide in accordance with thepresent invention.

FIG. 5 is an exploded view of a tissue anchor and introducer inaccordance with one aspect of the invention.

FIG. 6A is a schematic illustration of a tissue anchor and introduceradvancing into a tissue surface.

FIG. 6B is an illustration as in FIG. 6A, with the anchor positionedwithin the tissue and the introducer partially retracted.

FIG. 6C is an illustration as in FIG. 6B, with the introducer fullyrefracted and the anchor positioned within the tissue.

FIG. 7 shows a schematic view of a closure catheter disposed within theopening of the LAA.

FIG. 8 is a schematic illustration of the opening of the LAA as in FIG.7, with the anchor guides in an inclined orientation.

FIG. 9 is a schematic illustration as in FIG. 8, with tissue anchorsdeployed from the anchor guides.

FIG. 10 is a schematic illustration as in FIG. 9, with the anchor guidesretracted into an axial orientation.

FIG. 11 is a schematic illustration as in FIG. 10, with the closurecatheter retracted and the LAA drawn closed using the tissue anchors.

FIG. 11A is a schematic illustration of the distal tip of a deploymentcatheter, having an anchor suture loop with a slideable retentionstructure thereon.

FIG. 11B is a schematic illustration of a simplified Prusik knot,utilized as a component of the retention structure shown in FIG. 11A.

FIG. 11C is an enlargement of the retention structure shown in FIG. 11A.

FIG. 12 is a perspective view of a closure catheter in accordance withthe present invention positioned within a tissue aperture, such as anatrial septal defect.

FIG. 13 is a side elevational partial cross-section of the catheter ofFIG. 12, in an anchor deployment orientation within the aperture.

FIG. 14 is a side elevational partial cross-section as in FIG. 13, withthe deployment catheter withdrawn from the aperture.

FIG. 15 is a side elevational cross section through the aperture, whichhas been closed in accordance with the present invention.

FIG. 16 is a perspective view of a closure catheter in accordance withthe present invention, carrying an aperture patch.

FIG. 17 is a cross-sectional view through the catheter of FIG. 16, showndeploying a patch across a tissue aperture.

FIGS. 18A-18G are alternate tissue anchors for use with the closurecatheter of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

For simplicity, the present invention will be described primarily in thecontext of a left atrial appendage closure procedure. However, thedevice and methods herein are readily applicable to a wider variety ofclosure or attachment procedures, and all such applications arecontemplated by the present inventors. For example, additional heartmuscle procedures such as atrial septal defect closure and patent ductusarteriosis closure are contemplated. Vascular procedures such asisolation or repair of aneurysms, anastomosis of vessel to vessel orvessel to prosthetic tubular graft (e.g., PTFE or Dacron tubes, with orwithout wire support structures as are well known in the art) joints mayalso be accomplished using the devices of the present invention.Attachment of implantable prostheses, such as attachment of the annulusof a prosthetic tissue or mechanical heart valve may be accomplished. Avariety of other tissue openings, lumens, hollow organs and surgicallycreated passageways may be closed, patched or reduced in volume inaccordance with the present invention. For example, an opening in atissue plane may be closed or patched, such as by attaching a fabric ortissue sheet across the opening. In one specific application, the deviceof the present invention is used to anchor a fabric patch to close anatrial septal defect. The target aperture or cavity may be accessedtransluminally (e.g., vascular catheter or endoscope) or through solidtissue, such as transmural, percutaneous or other approach. The presentinvention may also be used in an open surgical procedure such as toclose the left atrial appendage during open heart surgery to correct oraddress a different condition. In another example, the device isadvanced through the percutaneous opening and used to close a vascularpuncture such as a femoral artery access site for a PTA or otherdiagnostic or therapeutic interventional procedure. Adaptation of thedevices and methods disclosed herein to accomplish procedures such asthe foregoing will be apparent to those of skill in the art in view ofthe disclosure herein.

Referring to FIG. 1, a heart 10 is illustrated to show certain portionsincluding the left ventricle 12, the left atrium 14, the left atrialappendage (LAA) 16, the pulmonary artery 18, the aorta 20, the rightventricle 22, the right atria 24, and the right atrial appendage 26. Asis understood in the art, the left atrium 14 is located above the leftventricle 12 and the two are separated by the mitral valve (notillustrated). The LAA 16 is normally in fluid communication with theleft atrium 14 such that blood flows in and out of the LAA 16 as theheart 10 beats.

In accordance with the present invention, a closure catheter 38 isadvanced through the heart and into the LAA. In general, the closurecatheter 38 is adapted to grasp tissue surrounding the opening to theLAA, and retract it radially inwardly to reduce the volume of and/orclose the LAA. The LAA is thereafter secured in its closed orientation,and the closure catheter 38 is removed. Specific aspects of oneembodiment of the closure catheter in accordance with the presentinvention are described in greater detail below.

The LAA may be accessed through any of a variety of pathways as will beapparent to those of skill in the art. Transeptal access, ascontemplated by FIG. 2, may be achieved by introducing a transeptalcatheter through the femoral or jugular vein, and transluminallyadvancing the catheter into the right atrium. Once in the right atrium,a long hollow needle with a preformed curve and a sharpened distal tipis forcibly inserted through the fossa ovalis. A radiopaque contrastmedia may then be injected through the needle to allow visualization andensure placement of the needle in the left atrium, as opposed to beingin the pericardial space, aorta, or other undesired location.

Once the position of the needle in the left atrium is confirmed, thetranseptal catheter is advanced into the left atrium. The closurecatheter 38 may then be advanced through the transeptal catheter 30, andsteered or directed into the left atrial appendage. Alternativeapproaches include venous transatrial approaches such as transvascularadvancement through the aorta and the mitral valve. In addition, thedevices of the present invention can be readily adapted for use in anopen heart surgical procedure, although transluminal access is presentlypreferred.

Thus, referring to FIG. 2, a transeptal catheter 30 has a proximal end32 and a distal end 34. The distal end 34 of the transeptal catheter 30has breached the septum 40 of the patient's heart 10 and is disposedadjacent the opening 42 of the patient's LAA 16. The distal end 36 of aclosure catheter 38 extends from the distal end 34 of the transeptalcatheter 30 and into the LAA 16.

At the proximal end 46 of the transeptal catheter 30, a luer connectorcoupled to a hemostasis valve 48 prevents the egress of blood from acentral lumen of the transeptal catheter 30. The proximal end 50 of theclosure catheter 38 extends proximally from the hemostasis valve 48.Additional details concerning the use and design of transeptal accesscatheters are well known in the art and will not be discussed furtherherein.

Referring to FIGS. 2 and 3, the closure catheter 38 thus has a proximalend 50, a distal end 36, and an elongate flexible tubular body 52extending therebetween. The axial length of the closure catheter 38 canbe varied, depending upon the intended access point and pathway. For afemoral vein-transeptal approach, the closure catheter 38 generally hasan axial length within the range of from about 100 cm to about 140 cm,and, in one embodiment, about 117 cm.

The outside diameter of the flexible body 52 can also be varied,depending upon the number of internal lumen and other functionalities aswill be understood by those of skill in the art. In one embodiment, theoutside diameter is about 12 FR (0.156 inches), and closure cathetersare contemplated to have OD's generally within the range of from about0.078 inches to about 0.250 inches. Diameters outside of the above rangemay also be used, provided that the functional consequences of thediameter are acceptable for the intended application of the catheter.

For example, the lower limit of the outside diameter for tubular body 52in a given application will be a function of the number of fluid orother functional lumen contained within the catheter. In addition,tubular body 52 must have sufficient pushability to permit the catheterto be advanced to its target location within the heart without bucklingor undesirable bending. The ability of the tubular body 52 to transmittorque may also be desirable, such as in embodiments in which the tissueanchor deployment guides are not uniformly circumferentially distributedabout the distal end 36 of the catheter. Optimization of the outsidediameter of the catheter, taking into account the flexibility,pushability and torque transmission characteristics can be accomplishedthrough routine experimentation using conventional catheter designtechniques well known to those of skill in the art.

The flexible body 52 can be manufactured in accordance with any of avariety of known techniques. In one embodiment, the flexible body 52 isextruded from any of a variety of materials such as HDPE, PEBAX, nylon,polyimide, and PEEK. Alternatively, at least a portion or all of thelength of tubular body 52 may comprise a spring coil, solid walledhypodermic needle or other metal tubing, or braided reinforced wall, asare known in the art.

The proximal end 50 of the closure catheter 38 is provided with amanifold 51, having a plurality of access ports. Generally, manifold 51is provided with an access port 53 which may be used as a guidewire portin an over the wire embodiment, and a deployment wire port 57.Additional access ports such as a contrast media introduction port 55,or others may be provided as needed, depending upon the functionalrequirements of the catheter.

The tubular body 52 has at least a first actuator lumen 54, for axiallymovably receiving an actuator 56. Actuator 56 extends between a proximalend 64 at about the proximal end of the closure catheter, and a distalend 66 at or near the distal end 36 of the closure catheter 38. Thedistal end 66 of the actuator 56 is secured to a cap 68. In theillustrated embodiment, the actuator lumen 54 is in communication withthe access port 53 to permit the actuator 56 to extend proximallytherethrough.

Actuator 56 can have a variety of forms, depending upon the constructionof the anchor supports 62 on the distal end 36 of the closure catheter38. In general, the catheter in the area of the anchor supports 62should have a crossing profile of no more than about 14 French fortransluminal advancement and positioning. However, the anchor supportsmust then be capable of directing tissue anchors into the wall of thecavity or lumen which may have an inside diameter on the order of about1.5 cm to about 3 cm in the case of the LAA in an average adult. Thedevice of the present invention can be readily scaled up or downdepending upon the intended use, such as to accommodate a 5 cm to 10 cmcavity in GI tract applications or 5 mm to about 2 cm for vascularapplications. For this purpose, the anchor supports are preferablymoveable between a reduced cross sectional orientation and an enlargedcross sectional orientation to aim at, and, in some embodiments, contactthe target tissue surface.

One convenient construction to accomplish the foregoing is for eachanchor support 62 to take the form of a lever arm structure which ispivotably connected at one end to the catheter body. This constructionpermits inclination of the anchor support throughout a continuous rangeof outside diameters which may be desirable to aim the anchor andaccommodate different treatment sites and/or normal anatomical variationwithin the patient population.

A laterally moveable anchor support can be moved between an axialorientation and an inclined orientation in a variety of ways. Oneconvenient way is through the use of a pull wire or other actuator whichincreases the diameter of the deployment zone of the catheter inresponse to an axial shortening of fixed length moveable segments asdisclosed in more detail below. For this construction, the actuator willbe under pulling tension during actuation. Any of a variety ofstructures such as polymeric or metal single or multiple strand wires,ribbons or tubes can be used. In the illustrated embodiment, theactuator 56 comprises stainless steel tube, having an outside diameterof about 0.025 inches.

A pull wire can alternatively be connected to the radially outwardlyfacing surface and preferably near the distal end of each anchorsupport, and each anchor support is hingably attached at its proximalend to the catheter. Proximal traction on the pull wire will cause theanchor support to incline radially outwardly in the distal direction,and toward the target tissue.

In an alternate construction, the anchor support is inclined under acompressive force on the actuator 56. For example, the embodimentdescribed in detail below can readily be converted to a push actuatedsystem by axially immovable fixing the distal end of the anchor guideassembly to the catheter and slideably pushing the proximal end of theanchor guide assembly in the distal direction to achieve axialcompression as will become apparent from the discussion below.

Push wire actuators have different requirements, than pull actuatorsystems, such as the ability to propagate a sufficient compressive forcewithout excessive compression bending or friction. Thus, solid corewires or tubular structures may be preferred, as well as larger outsidediameters compared to the minimum requirements in a pull actuatedsystem. Thus, the inside diameter of the actuator lumen 57 may bevaried, depending upon the actuator system design. In the illustratedembodiment, the actuator lumen 57 has an ID of about 0.038 inches, toslideably accommodate the 0.025 inch OD actuator 56.

A radially outwardly directed force on the anchor supports 62 can beprovided by any of a variety of alternative expansion structures,depending upon desired performance and construction issues. For example,an inflatable balloon can be positioned radially inwardly from aplurality of hingably mounted anchor supports 62, and placed incommunication with actuator lumen 54 which may be used as an inflationlumen. Any of a variety of balloon materials may be used, ranging inphysical properties from latex for a highly compliant, low pressuresystem to PET for a noncompliant high pressure and consequently highradial force system, as is understood in the balloon angioplasty arts.

The tubular body 52 may additionally be provided with a guidewire lumen57, or a guidewire lumen 57 may extend coaxially throughout the lengthof a tubular actuator 56 as in the illustrated embodiment.

The tubular body 52 may additionally be provided with a deployment lumen58, for axially movably receiving one or more deployment elements 60such as a wire, or suture for deploying one or more tissue anchors 90into the target tissue 110. Deployment force for deploying the tissueanchors 90 can be designed to be in either the distal or proximaldirection, and many of the considerations discussed above in connectionwith the actuator 56 and corresponding actuator lumen 54 apply to thedeployment system as well. In the illustrated embodiment, deployment ofthe tissue anchors 90 is accomplished by proximal retraction on thedeployment element 60 which, in turn, retracts deployment wire 106.Pushability is thus not an issue, and common suture such as 0.008 inchdiameter nylon line may be used. For this embodiment, deployment lumen58 has an inside diameter of about 0.038 inches. The deployment lumen 58can be sized to receive either a single deployment element 60, or aplurality of deployment elements 106 such as a unique suture for eachtissue anchor.

The distal end 36 of the closure catheter 38 is provided with one ormore anchor supports 62, for removably carrying one or more tissueanchors. Preferably, two or more anchor supports 62 are provided, and,generally, in a device intended for LAA closure, from about 3 to about12 anchor supports 62 are provided. In the illustrated embodiment, sixanchor supports 62 are evenly circumferentially spaced around thelongitudinal axis of the closure catheter 38.

Each anchor support 62 comprises a surface 63 for slideably retaining atleast one tissue anchor, and permitting the tissue anchor to be aimed bymanipulation of a control on the proximal end 50 of the closure catheter38. Specific details of one embodiment of the anchor support 62 having asingle anchor therein will be discussed below. Multiple anchors, such astwo or three or more, can also be carried by each anchor support forsequential deployment.

The anchor supports 62 are movable between an axial orientation and aninclined orientation, in response to manipulation of a proximal control.The proximal control can take any of a variety of forms, such as sliderswitches or levers, rotatable levers or knobs, or the like, dependingupon the desired performance. For example, a rotatable knob control canpermit precise control over the degree of inclination of the anchorsupports 62. A direct axial slider control, such as a knob or other gripdirectly mounted to the actuator 56 will optimize tactile feedback ofevents such as the anchor supports 62 coming into contact with thetarget tissue.

Each of the illustrated anchor supports 62 comprises at least a proximalsection 70, a distal section 72, and a flex point 74. See FIG. 4. Thedistal end 73 of each distal section 72 is movably connected to thecatheter body or the cap 68. In this embodiment, proximal retraction ofthe actuator 56 shortens the axial distance between the proximal end 71of the proximal section 70 and the distal end 73 of distal section 72,forcing the flex point 74 radially outwardly from the longitudinal axisof the closure catheter 38. In this manner, proximal retraction of theactuator 56 through a controlled axial distance will cause a predictableand controlled increase in the angle between the proximal and distalsections 70 and 72 of the anchor support 62 and the longitudinal axis ofthe catheter. This is ideally suited for aiming a plurality of tissueanchors at the interior wall of a tubular structure, such as a vessel orthe left atrial appendage.

Referring to FIG. 4, there is illustrated an enlarged detailed view ofone anchor support 62 in accordance with the present invention. Theproximal section 70 and distal section 72 preferably comprise a tubularwall 76 and 78 joined at the flex point 74. In one embodiment, theproximal section 70 and distal section 72 may be formed from a singlelength of tubing, such as by laser cutting, photolithography, orgrinding to separate the proximal section 70 from the distal section 72while leaving one or two or more integrally formed hinges at flex point74. Any of a variety of polymeric or metal tubing may be utilized forthis purpose, including stainless steel, Nitinol or other super-elasticalloys, polyimide, or others which will be appreciated by those of skillin the art in view of the disclosure herein.

In the illustrated six tube embodiment, the proximal section 70 anddistal section 72 are formed from a length of PEEK tubing having aninside diameter of about 0.038 inches, an outside diameter of about0.045 inches and an overall length of about 1.4 inches. In general, ifmore than six anchor supports 62 are used, the diameter of each will becommensurately less than in the six tube embodiment for any particularapplication. When the proximal section 70 and the distal section 72 arecoaxially aligned, a gap having an axial length of about 0.030 isprovided therebetween. In the illustrated embodiment, the proximalsection 70 and distal section 72 are approximately equal in lengthalthough dissimilar lengths may be desirable in certain embodiments. Thelength of the portion of the anchor support 62 which carries the tissueanchor 90 is preferably selected for a particular procedure or anatomyso that the anchor support 62 will be inclined at an acceptable launchangle when the deployment end of the anchor support 62 is brought intocontact with the target tissue 110. Lengths from the hinge to thedeployment end of the anchor support 62 within the range of from about0.5 cm to about 1.5 cm are contemplated for the LAA applicationdisclosed herein.

For certain applications, the proximal section 70 is at least about 10%and preferably at least about 20% longer than the distal section 72. Forexample, in one device adapted for the LAA closure application, theproximal section 70 in a six anchor device has a length of about 0.54inches, and the distal section 72 has a length of about 0.40 inches.Each anchor support has an OD of about 0.045 inches. As with previousembodiments, the functional roles and/or the dimensions of the proximaland distal sections can be reversed and remain within the scope of thepresent invention. Optimization of the relative lever arm lengths can bedetermined for each application taking into account a variety ofvariables such as desired device diameter, target lumen or tissueaperture diameter, launch angle and desired pull forces for aiming anddeployment.

The proximal end 71 of the proximal section 70 and distal end 73 ofdistal section 72 are movably secured to the closure catheter 38 in anyof a variety of ways which will be apparent to those of skill in the artin view of the disclosure herein. In the illustrated embodiment, eachanchor support 62 comprises a four segment component which may beconstructed from a single length of tubing by providing an intermediateflex point 74, a proximal flex point 80 and a distal flex point 82.Distal flex point 82 provides a pivotable connection between the anchorsupport 62 and a distal connection segment 84. The distal connectionsegment 84 may be secured to the distal end of actuator 56 by any of avariety of techniques, such as soldering, adhesives, mechanical interfitor others, as will be apparent to those of skill in the art. In theillustrated embodiment, the distal connection segment 84 is secured tothe distal end 66 of the actuator 56 by adhesive bonding.

The proximal flex point 80 in the illustrated embodiment separates theproximal section 70 from a proximal connection segment 86, which isattached to the catheter body 52. In this construction, proximal axialretraction of the actuator 56 with respect to the tubular body 52 willcause the distal connection segment 84 to advance proximally towards theproximal connection segment 86, thereby laterally displacing the flexpoint 74 away from the longitudinal axis of the closure catheter 38. Asa consequence, each of the proximal section 70 and the distal section 72are aimed at an angle which is inclined outwardly from the axis of theclosure catheter 38.

In general, each flex point 80, 82 includes a hinge 81, 83 which may be,as illustrated, a strip of flexible material. The hinges 81 and 83 arepreferably positioned on the inside radius of the flex points 80, 82,respectively, for many construction materials. For certain materials,such as Nitinol or other superelastic alloys, the hinges 81 and 83 canbe positioned at approximately 90.degree. or 180.degree. or other anglearound the circumference of the tubular anchor guide from the insideradius of the flex point.

A tissue anchor 90 is illustrated as positioned within the distalsection 72, for deployment in a generally proximal direction.Alternatively, the anchor 90 can be loaded in the proximal section 70,for distal deployment. A variety of tissue anchors can be readilyadapted for use with the closure catheter 38 of the present invention,as will be appreciated by those of skill in the art in view of thedisclosure herein. In the illustrated embodiment, the tissue anchor 90comprises a tubular structure having a body 92, and one or more barbs94. Tubular body 92 is coaxially movably disposed about an introducer96. Introducer 96 has a proximal section 98, and a sharpened distal tip100 separated by an elongate distal section 102 for slideably receivingthe tissue anchor 90 thereon.

The tissue anchor 90 in the illustrated embodiment comprises a tubularbody 92 having an axial length of about 0.118 inches, an inside diameterof about 0.017 inches and an outside diameter of about 0.023 inches. Twoor more barbs 94 may be provided by laser cutting a pattern in the wallof the tube, and bending each barb 94 such that it is biased radiallyoutwardly as illustrated. The tissue anchor 90 may be made from any of avariety of biocompatible metals such as stainless steel, Nitinol,Elgiloy or others known in the art. Polymeric anchors such as HDPE,nylon, PTFE or others may alternatively be used. For embodiments whichwill rely upon a secondary closure structure such as staples, sutures orclips to retain the LAA or other cavity closed, the anchor may comprisea bioabsorbable or dissolvable material so that it disappears after aperiod of time. An anchor suture 108 is secured to the anchor.

In one embodiment of the invention, the introducer 96 has an axiallength of about 0.250 inches. The proximal section 98 has an outsidediameter of about 0.023 inches and an axial length of about 0.100inches. The distal section 102 has an outside diameter of about 0.016inches and an axial length of about 0.150 inches. The outside diametermismatch between the proximal section 98 and the distal section 102provides a distally facing abutment 104, for supporting the tubular body92 of tissue anchor 90, during the tissue penetration step. A deploymentwire (e.g., a suture) 106 is secured to the proximal end 98 of theintroducer 96. The introducer 96 may be made in any of a variety ofways, such as extrusion or machining from stainless steel tube stock.

Referring to FIGS. 6A-6C, introduction of the tissue anchor 90 intotarget tissue 110 is illustrated following inclination of the anchorsupport 62 with respect to the longitudinal axis of the closure catheter38. Proximal retraction of the deployment wire 106 causes the tissueanchor 90 and introducer 96 assembly to travel axially through thedistal section 72, and into the tissue 110. Continued axial fraction onthe deployment wire 106 causes the longitudinal axis of the introducer96 to rotate, such that the introducer 96 becomes coaxially aligned withthe longitudinal axis of the proximal section 70. Continued proximaltraction on the deployment wire 106 retracts the introducer 96 from thetissue anchor 90, leaving the tissue anchor 90 in place within thetissue. The anchor suture 108 remains secured to the tissue anchor 90,as illustrated in FIG. 6C.

In use, the closure catheter 38 is percutaneously introduced into thevascular system and transluminally advanced into the heart and,subsequently, into the left atrial appendage using techniques which areknown in the art. Referring to FIG. 7, the distal end 36 of the closurecatheter 38 is positioned at about the opening of the LAA 16, and theposition may be confirmed using fluoroscopy, echocardiography, or otherimaging. The actuator 56 is thereafter proximally retracted, to inclinethe anchor supports 62 radially outwardly from the longitudinal axis ofthe closure catheter 38, as illustrated in FIG. 8. Preferably, the axiallength of the proximal section 70 of each anchor support 62, incombination with the angular range of motion at the proximal flex point80, permit the flex point 74 to be brought into contact with the tissuesurrounding the opening to the LAA. In general, this is preferablyaccomplished with the distal section 72 inclined at an angle within arange of from about 45.degree. to about 120.degree. with respect to thelongitudinal axis of the closure catheter 38. Actuator 56 may beproximally retracted until the supports 62 are fully inclined, or untiltactile feedback reveals that the anchor supports 62 have come intocontact with the surrounding tissue 110.

Following inclination of the anchor supports 62, the deployment wire 106is proximally retracted thereby advancing each of the tissue anchors 90into the surrounding tissue 110 as has been discussed. See FIG. 9. Theanchor supports 62 are thereafter returned to the first, axial position,as illustrated in FIG. 10, for retraction from the left atrialappendage. Proximal retraction on the anchor sutures 108 such as througha tube, loop or aperture will then cause the left atrial appendage wallto collapse as illustrated in FIG. 11. Anchor sutures may thereafter besecured together using any of a variety of conventional means, such asclips, knots, adhesives, or others which will be understood by those ofskill in the art. Alternatively, the LAA may be sutured, pinned, stapledor clipped shut, or retained using any of a variety of biocompatibleadhesives.

In one embodiment, a single suture 108 is slideably connected to aplurality of anchors such that proximal retraction of the suture 108following deployment of the anchors draws the tissue closed in a “pursestring” fashion. A similar technique is illustrated in FIGS. 31A and 31Bin U.S. Pat. No. 5,865,791 to Whayne, et al., the disclosure of which isincorporated in its entirety herein by reference.

Depending upon the size and anatomical forces working on the aperture orlumen to be closed, anywhere from 2 to about 12 or more anchors may bespaced around the circumference of the opening using any of thedeployment catheters disclosed herein. Preferably, from about 3 to about8 anchors, and, in one “purse string” embodiment, six anchors areutilized in the context of closing an atrial septal defect. However, theprecise number and position of the anchors surrounding an atrial septaldefect or other aperture can be varied depending upon the anatomy, andclinical judgment as will be apparent to those of skill in the art.

Referring to FIGS. 11A-11C the distal end 36 of a deployment catheter isschematically illustrated following deployment of a plurality of anchors90. Only two anchors are illustrated for simplicity. An anchor suture108 extends in a loop 113, and slideably carries each of the anchors 90.A retention structure 109 is slideably carried by first and secondportions of the anchor suture 108, such that distal advancement of theretention structure 109 along the suture 108 causes the loop 113 formedby the distal portion of anchor suture 108 and retention structure 109to decrease in circumference, such as would be accomplished during areduction of the size of the tissue aperture or lumen.

Preferably, the retention structure 109 may be advanced distally alongthe suture 108 to close the loop 113 such as by proximally retractingthe suture 108 into the deployment catheter and contacting the retentionstructure 109 against a distal surface 69 which may be on the cap 68 orother aspect of the distal end 36 of the catheter. In the illustratedembodiment, the retention structure 109 includes a first Prusik knot 115and a second Prusik knot 117, slideably carried on the suture 108. Thefirst and second Prusik knots 115, 117 are secured together such as by asquare knot 119. Any of a variety of other knots, links or otherconnections may alternatively be utilized.

The foregoing closure techniques may be accomplished through the closurecatheter, or through the use of a separate catheter. The closurecatheter may thereafter be proximally retracted from the patient, andthe percutaneous and vascular access sites closed in accordance withconventional puncture closure techniques.

In accordance with a further aspect of the present invention, theclosure catheter 38 with modifications identified below and/or apparentto those of skill in the art in view of the intended application, may beutilized to close any of a variety of tissue apertures. These include,for example, atrial septal defects, ventricle septal defects, patentductus arteriosis, patent foreman ovale, and others which will beapparent to those of skill in the art. Tissue aperture closuretechniques will be discussed in general in connection with FIGS. 12-17.

Referring to FIG. 12, there is schematically illustrated a fragmentaryview of a tissue plane 120 such as a septum or other wall of the heart.Tissue plane 120 contains an aperture 122, which is desirably closed.The closure catheter 38 is illustrated such that at least a portion ofthe distal end 36 extends through the aperture 122. Although the presentaspect of the invention will be described in terms of a retrograde orproximal tissue anchor advancement from the back side of the tissueplane, the anchor deployment direction can readily be reversed by one ofordinary skill in the art in view of the disclosure herein, and themodifications to the associated method would be apparent in the contextof a distal anchor advancement embodiment. In general, the proximalanchor advancement method, as illustrated, may desirably assist incentering of the catheter within the aperture, as well as permittingpositive traction to be in the same direction as anchor deployment.

Closure catheter 38 is provided with a plurality of anchor supports 62as have been described previously herein. In an embodiment intended foratrial septal defect closure, anywhere within the range of from about 3to about 12 anchor supports 62 may be utilized.

Referring to FIG. 13, each anchor support 62 comprises a proximalsection 70, a distal section 72, and a hinge or flex point 74therebetween as has been previously discussed. At least one anchor 90 iscarried by each anchor support 62, such as within the tubular distalsection 72 in the context of a proximal deployment direction embodiment.Anchor 90 is connected to an anchor suture 108 as has been discussed. Inthe illustrated embodiment, the anchor suture 108 extends along theoutside of the anchor support 62 and into the distal opening of a lumenin tubular body 52. The anchor sutures 108 may, at some point, be joinedinto a single element, or distinct anchor sutures 108 may extendthroughout the length of the catheter body to the proximal end thereof

As shown in FIG. 13, the anchor support 62 is advanced from a generallyaxially extending orientation to an inclined orientation to facilitatedeployment of the anchor 90 into the tissue plane 120 adjacent aperture122. Preferably, the geometry of the triangle defined by distal section72, proximal section 70 and the longitudinal axis of the catheter isselected such that the plurality of anchors 90 will define a roughlycircular pattern which has a greater diameter than the diameter ofaperture 122. Thus, the length of proximal section 70 will generally begreater than the approximate radius of the aperture 122.

In general, for atrial septal defect applications, the circle which bestfits the anchor deployment pattern when the distal section 72 isinclined to its operative angle will have a diameter within the range offrom about 0.5 centimeters to about 3 centimeters. Dimensions beyondeither end of the foregoing range may be desirable to correct defects ofunusual proportions. In addition, it is not necessary that the anchorsdefine a circular pattern when deployed into the tissue plane 120.Non-circular patterns such as polygonal, elliptical, oval or other, maybe desirable, depending upon the nature of the aperture 122 to beclosed.

FIG. 13 illustrates the anchors 90 partially deployed into or throughthe tissue plane 120. In general, the anchors 90 may either be designedto reside within the tissue plane 120 such as for locations of theaperture 120 which are adjacent relatively thick tissues. Alternatively,the tissue anchor 90 may be designed to reside on one side of the tissueplane 120, and attached to a suture which extends through the tissueplane 120 as illustrated in FIGS. 14 and 15.

Referring to FIG. 14, the closure catheter 38 is illustrated as returnedto the generally axial orientation and proximally retracted through theaperture 122 following deployment of a plurality of tissue anchors 90.The anchor sutures 108 may thereafter be proximally refracted from theproximal end of the closure catheter 38, thereby drawing the tissuesurrounding aperture 122 together to close the aperture. The anchorsutures 108 may thereafter be secured together in any of a variety ofmanners, such as by clamping, knotting, adhesives, thermal bonding orthe like.

In the illustrated embodiment, the closure catheter 38 carries adetachable clamp 124 which may be deployed from the distal end of theclosure catheter 38 such as by a push wire, to retain the anchor sutures108. The clamp 124 may be an annular structure with an aperture thereinfor receiving the anchor sutures 108. The clamp is carried on thecatheter in an “open” position and biased towards a “closed” position inwhich it tightens around the sutures 108. A ring of elastomeric polymer,a relatively inelastic but tightenable loop such as a ligating band, ora shape memory metal alloy may be used for this purpose. Any of avariety of clamps, clips, adhesives, or other structures may be utilizedto secure the anchor sutures 108 as will be appreciated by those ofskill in the art in view of the disclosure herein. Anchor sutures 108may thereafter be severed such as by mechanical or thermal means, andthe closure catheter 38 is thereafter retracted from the treatment site.

Alternatively, elastic bands or other forms of the clamp may be deployedto directly clamp the tissue and hold the aperture closed. In thisapplication, the closure catheter is used to attach a plurality ofanchors spaced around the circumference of the aperture. The anchors aredrawn radially inwardly towards each other by proximal traction on oneor more sutures. Further proximal traction on the one or more suturespulls the aperture edges proximally out of the tissue plane. Thepartially everted aperture can then be secured closed by deploying aclamp there around. As used herein, “clamp” includes all of the elasticband, ligating band, metal clips and other embodiments disclosed herein.

In accordance with a further aspect of the present invention, theclosure catheter 38 is provided with a deployable patch 126, asillustrated in FIGS. 16 and 17. The patch 126 may comprise of any of avariety of materials, such as PTFE, Dacron, or others depending upon theintended use. Suitable fabrics are well-known in the medical device art,such as those used to cover endovascular grafts or other prostheticdevices.

The patch 126 is preferably carried by the distal sections 72 of theanchor support 62. In the illustrated embodiment, the tissue anchors 90are carried within the proximal section 70 of anchor support 62. In thismanner, as illustrated in FIG. 17, the patch 126 is automaticallyunfolded and positioned across the aperture 122 as the anchor supports62 are inclined into the anchor deployment orientation. The tissueanchor 90 may thereafter be advanced through the patch 126 and into thetissue plane 120 to tack the patch 126 against the opening 122.Alternatively, the tissue anchors may be deployed in a pattern whichsurrounds but does not penetrate the tissue patch. In this embodiment,the tissue anchors are preferably connected to the tissue patch such asby a suture. The tissue anchors may also both be connected to the patchor to each other by sutures and penetrated through the patch into thetarget tissue.

Tissue anchors 90 may be deployed proximally by pulling the deploymentwire 106. Alternatively, tissue anchors 90 with or without an anchorsuture 108, may be deployed from the proximal section 70 by a push wireaxially movably positioned within the proximal section 70. Tissueanchors 90 may be carried on an introducer 96 as has been discussedpreviously herein.

The patch 126 may be retained on the distal section 72 in any of avariety of ways, such as through the use of low strength adhesivecompositions, or by piercing the anchors 90 through the material of thepatch 126 during the catheter assembly process.

The cardiac defects may be accessed via catheter through a variety ofpathways. An ASD or VSD may be accessed from the arterial circuit. Thecatheter is introduced into the arterial vascular system and guided upthe descending thoracic and/or abdominal aorta. The catheter may then beadvanced into the left ventricle (LV) through the aortic outflow tract.Once in the LV, the closure anchors may be deployed in the VSD.Alternatively, once in the LV, the catheter may be directed up throughthe mitral valve and into the left atrium (LA). When the catheter is inthe LA, it may be directed into the ASD and the anchors deployed.

Alternatively, an ASD or VSD may be accessed from the venous circuit.The catheter may be introduced into the venous system, advanced into theInferior Vena Cava (IVC) or Superior Vena Cava (SVC) and guided into theright atrium (RA). The catheter may then be directed into the ASD.Alternatively, once in the RA, the catheter may be advanced through thetricuspid valve and into the right ventricle (RV) and directed into theVSD and the anchors deployed.

Referring to FIGS. 18A-18G, there are illustrated a variety of tissueanchors which may be used in the tissue closure or attachment device ofthe present invention. Each of FIGS. 18A and 18B disclose an anchorhaving a body 92, a distal tip 101, and one or more barbs 94 to resistproximal movement of the anchor. An aperture 107 is provided to receivethe anchor suture. The embodiments of FIGS. 18A and 18B can be readilymanufactured such as by stamping or cutting out of flat sheet stock.

The anchor illustrated in FIG. 18C comprises a wire having a body 92 anda distal tip 101. The wire preferably comprises a super-elastic alloysuch as Nitinol or other nickel titanium-based alloy. The anchor iscarried within a tubular introducer, in a straight orientation, forintroduction into the tissue where the anchor is to reside. As the body92 is advanced distally from the carrier tube, the anchor resumes itslooped distal end configuration within the tissue, to resist proximalretraction on the wire body 92.

FIG. 18D illustrates a tubular anchor, which may be manufactured from asection of hypotube, or in the form of a flat sheet which is thereafterrolled about a mandrel and soldered or otherwise secured. The anchorcomprises a distal tip 101, one or more barbs 94, and an aperture 107for securing the anchor suture. The anchor of FIG. 18D may be carried byand deployed from the interior of a tubular anchor support as has beendiscussed. Alternatively, the anchor of FIG. 18D can be coaxiallypositioned over a central tubular or solid anchor support wire.

FIG. 18E illustrates an anchor which may be formed either by cuttingfrom tube stock or by cutting a flat sheet such as illustrated in FIG.18F which is thereafter rolled about an axis and soldered or otherwisesecured into a tubular body. In this embodiment, three distal tips 101in the flat sheet stock may be formed into a single distal tip 101 inthe finished anchor as illustrated in FIG. 18E. One or more barbs 94 maybe formed by slotting the sheet in a U or V-shaped configuration asillustrated. The anchor in FIG. 18E is additionally provided with one ormore barbs 95 which resist distal migration of the anchor. This may bedesirable where the anchor is implanted across a thin membrane, or inother applications where distal as well as proximal migration isdesirably minimized.

Although the present invention has been described in terms of certainpreferred embodiments, other embodiments will become apparent to thoseof skill in the art in view of the disclosure herein. Accordingly, thescope of the invention is not intended to be limited by the specificdisclosed embodiments, but, rather, by the attached claims.

What is claimed:
 1. A method of preventing passage of embolic materialfrom a left atrial appendage, comprising: positioning a patch across anopening of the left atrial appendage; and securing the patch at one ormore locations surrounding the opening of the left atrial appendage.